Give to Solomon my son a perfect heart, to keep Your commandments, Your testimonies, and Your Statutes. (1 Chronicles 29:19)
Let my heart be perfect in Your testimonies. (Psalm 119:80)
The perfect heart is a gift from God, given and received under the laws which rule all His giving, as a hidden seed to be accepted and acted on in faith. The command, “Be perfect,” comes and claims immediate and full submission. Where this submission is yielded, the need of a Divine power to make the heart fit for perfections becomes the motive for urgent and earnest prayer. The word of command, received and hid in a good and honest heart, becomes itself the seed of a Divine power. God works His grace in us by stirring us to work. So the desire to listen to God’s command, and to serve Him with a perfect heart, is a beginning that God looks to, and that He will Himself strengthen and perfect.
The gift of a perfect heart is thus obtained in the way of the obedience of faith. Begin at once to serve God with a perfect heart, and the perfect heart will be given to you. The perfect heart is a gift from God, to be asked for, to be obtained by prayer. No one will pray for it earnestly, perseveringly, believingly, until he accepts God’s word fully that is a positive command and an immediate duty to be perfect. Where this has been done, the consciousness will soon grow strong of the utter impossibility of attempting obedience in human strength. And the faith will grow that the word of command was simply meant to draw the soul to Him who gives what he asks. The perfect heart is a gift to be obtained by prayer. – Andrew Murray